Video Shows Hacker Attack on Power Plant

Researchers who launched an experimental cyber attack caused a generator to self-destruct, alarming the federal government and electrical industry about what might happen if such an attack were carried out on a larger scale, CNN has learned.

Sources familiar with the experiment said the same attack scenario could be used against huge generators that produce the country's electric power. Some experts fear bigger, coordinated attacks could cause widespread damage to electric infrastructure that could take months to fix.

In a previously classified video of the test CNN obtained, the generator shakes and smokes, and then stops.

DHS acknowledged the experiment involved controlled hacking into a replica of a power plant's control system. Sources familiar with the test said researchers changed the operating cycle of the generator, sending it out of control.

The White House was briefed on the experiment, and DHS officials said they have since been working with the electric industry to devise a way to thwart such an attack.